Simple shader used on shape entities has incorrect shading in Forward renderer

[ada-tv]

Looks a bit like bad normals to me?

Test case

• Sky and ambient color #808080, intensity 1.0
• Sun color #ffffff, intensity 2.0
• Cylinder shape with color #606060, both on the shape and on the material albedo color (though are rendered with different final colors?)

Example images

• Simple shader, Forward
• Simple shader, Deferred
• Material shader, Forward
• Material shader, Deferred

[ada-tv]

I think this also affects the background of Text entities in forward rendering too

[HifiExperiments]

regarding the difference for materials, I think it's probably an rbg/srgb difference (you can set whether or not a material color is srgb by passing a boolean as the 4th component to to the array: https://apidocs.overte.org/global.html#RGBS)

regarding the shading difference, that's definitely weird, since these two paths should be the same: https://github.com/overte-org/overte/blob/3aed07517a1c3ab3f1df9a1ac163ef2213678754/libraries/render-utils/src/simple.slf#L115-L142

I'm suspicious of the fresnel calculation, although that should match the deferred path